New 400 kHz Current Sensors Enable More Sustainable Designs in Switch-Mode Power Designs
New 400 kHz Current Sensors Enable More Sustainable Designs in Switch-Mode Power Designs
By Wade Bussing, Product Marketing Engineer, Allegro MicroSystems
Really Cool. Really Efficient.
主要通过成本和缩小PCB区域驱动，系统设计人员在其开关模式功率设计中为更小的无源元件和上集成传感器解决方案。较小电容器和电感器的节省空间以开关损耗的形式牺牲效率，因为需要更高的开关速度来产生等效的功率。
The availability of wide bandgap devices (SiC, GaN, and GaAs) has reduced the impact of switching losses on efficiency. As such, switching frequencies are on the rise in many power applications, including DC to DC converters, solar MPPT and inverters, telecom and server power supplies, power distribution units (PDUs), uninterruptible power supplies (UPS), and charging stations.
With these new gains in efficiency and space savings, the high-speed trend is expected to continue, creating new requirements for current monitoring and protection. Allegro’s broad family of integrated Hall-effect current sensor ICs have kept pace with this high-speed trend by offering innovative high-speed solutions without sacrificing on size, efficiency, or performance.
稳定性和准确性
Switching frequency directly affects a power system’s response to transient loads. As power supplies are tasked with supporting multiple subsystems, a proper transient response is required to avoid brownout events as these subsystems come online. When choosing sensors for such applications, system architects typically compromise between high speed or stability and accuracy over frequency and temperature. Compare the unfiltered response of two current sensing solutions in Figure 1.
The underdamped response of competing solutions creates ambiguity during peak current detection leading to errors in control and a reduction in overall efficiency. Output ringing also triggers overcurrent events, false shutdowns, and “nuisance” faults.
With the ACS37002, system architects no longer need to compromise. Thanks to an innovative 400 kHz signal path and mature sensor architecture, the ACS37002 cleanly tracks the signal with minimal ringing, phase delay, or attenuation—and no external filter components. A differential output (Vref) and stray field rejection offer high signal integrity in noisy environments. This integrated current sensor from Allegro occupies a new sweet spot for high speed, high accuracy, and rock-solid stability over frequency and temperature.
效率，加热和PCB区域
频率不是上升的唯一规范。效率目标也在增加，推动了采用低损耗开关技术。随着开关的导通电阻下降，当前路径中的其他组件开始占加热损失的更高百分比的功率。
I2R损失管理对系统成本和可靠性具有复杂的影响。限制热量降低了冷却要求和相关成本，同时延长了电力系统的寿命和可靠性。对于太阳能逆变器等设备，这在阳光下的更多时间，维护或垃圾填埋场更少。表1比较了标准电流传感解决方案的损失。
Power loss in shunt solutions is reduced by placing additional resistors in parallel or choosing lower resistor values. These methods are useful, but the layout is critical for overall accuracy, and the added resistors consume precious board space—especially when oversized. Lastly, most shunt solutions do not support negative input voltages, requiring additional isolation components to make the measurement.
Conclusion
The latest generation of current sensors are easy to use and are up-integrated with features that reduce design time, BOM size, and cost. As a result, system architects may focus on the unique and challenging aspects of their design.
The 400 kHz ACS37002 family of sensors is cool under heavy workloads, with a compact, low power loss package that keeps temperatures down and can extend the life of a power system. These current sensors hit the right balance of high speed, high accuracy, and stability over temperature, making switched-mode power designs greener and more efficient—leading technology and the world to a more sustainable future.